Shaykh Muhammad Ibn Hizaam was asked:
What is the ruling on hanging posters in the wudu area and in other than it, which call/indicate towards the cleanliness of the masjid? And this is not inside the prayer hall of the masjid.
“There is no harm. It is permissible. That is: some notifications are permissible and there is no preventative in the Legislation for that”.
Faisal Ibn Abdul Qaadir Ibn Hassan